You don't do blood testing after a single shot. Usually you wait 6-8 weeks to re-test, so to let your hormone levels reach a stable level.
Also, 250mg in just one shot is a huge amount that is very likely going to create more issues.
Most people start with just 100mg a week (preferably divided in two shots) and adjust the dosage after 6-8 weeks, accordingly to the blood test results.